Airline meals are typically prepared in advance by caterers. In one approach, a caterer prepares a large quantity of individual meals and stores them in a refrigeration locker. The refrigeration locker is typically kept at a temperature between 35° F. and 40° F. because the United States Public Health Service (USPHS) requires that airlines not serve food whose temperature has risen above 45° F. In preparation for a flight, the caterer takes the required quantity of meals out of the locker and places them in aircraft galley carts. Alternatively, the meals could be placed in the galley carts prior to storage in the refrigeration locker. The caterer then transports the galley carts to the aircraft and loads them into a galley.
Airline operators typically use one of two methods to keep the meals below the maximum allowable 45° F. while they are stored in the aircraft galley. Both of these methods utilize a galley chilled-air refrigeration system. The first method uses an “air-over” approach to flow chilled air from the aircraft refrigeration system over and around the galley carts when they are stored in the galley. The second method uses an “air-through” approach to flow chilled air from the aircraft refrigeration system through each of the individual galley carts in the aircraft galley.
One shortcoming associated with the conventional food chilling methods is that the galley chilled-air refrigeration system draws a significant amount of electrical power from the aircraft power system. Another shortcoming of these methods is that the galley chilled-air refrigeration system increases the cost and weight of the aircraft. A further shortcoming of these methods is that they lack a means for ensuring that the meals have not exceeded the 45° F. maximum allowable temperature set by the USPHS.